Myxamoebae of Didymium iridis, Physarum polycephalum, Physarum flavicomum, and Didtypostelium discoideum will be studied to determine the relation of cell surface and membrane structure to sexual fusion processes. Freeze-fracture, scanning electron microscopy, and cell fractionation techniques will be employed. We expect to isolate and biochemically characterize plasma membranes. In a subsidiary project, we will attempt to localize wheat germ agglutinin binding sites on CHO cells using gold-labelled lectins.